I used to volunteer a lot for different causes. But now choosing different projects mainly deforestation. As well wondering to choose some monthly thing in connection with education/poverty/environmental.
Actually had an experience to collect money in the streets for AIDS education and support in developing countries. Well it was very very hard! But we all needed to have a special permit to do so and just in designated places as well it was just one day permit, special boxes so no one could take money out, label ect. And it was just cash no monthly subscription.
Honestly I prefer to make donations online or to volunteer where support is needed.